DE69937244T2 - PROCESS FOR THE PREPARATION OF FLUOROETHANE - Google Patents

Abstract

Fluorochromium oxide having a fluorine content of not less than 30 wt.% is used for the fluorination reaction. To provide a manufacturing method for fluorine-containing ethane which contains 1, 1, 1, 2, 2-pentafluoroethane as the main component in which the reaction can be performed while controlling the generation of CFCs to the greatest possible extent by fluorinating at least one selected from the group composed of tetrachloroethylene, 2, 2-dichloro-1, 1, 1-trifluoroethane and 2-chloro-1, 1, 1, 2-tetrafluoroethane with hydrogen fluoride.

Description

THE iNVENTION field

The The present invention relates to a fluorine-containing production process Ethane to 2-chloro-1,1,1,2-tetrafluoroethane (in places as HCFC-124 abbreviated) and / or 2,2-dichloro-1,1,1-trifluoroethane (abbreviated in places as HCFC-123) as well as 1,1,1,2,2-pentafluoroethane (abbreviated in places as HFC-125) as Main reaction products to obtain.

State of the art

HFC-125 is used as a component in an alternative to 1-chloro-1,1-difluoromethane (HCFC-22) refrigerant gas (refrigerant), since its ozone destruction coefficient is zero. As a manufacturing process for HFC-125 using HCFC-124 as a material is in the publication USP No. 5,475,167 a production method using chromium oxide (Cr ₂ O ₃ ) as a catalyst as a patent for regulating the formation of CFCs (which are currently banned because they damage the ozone layer). In the process described in this publication, a conversion into HCFC-125 of not less than 50% is described as necessary. Also, in the method described in Examples, a high specific surface area Cr ₂ O ₃ catalyst prepared from (NH ₄ ) ₂ Cr ₂ O ₇ or one further treated with CO, H _2, and H ₂ O is used , When these catalysts are used, the amount of CFCs formed is 0.3 mole% of HFC-125.

Next will be in the publication USP No. 5,334,787 described a production method of HFC-125 from HCFC-123 or HCFC-124 by a gas phase reaction using Cr ₂ O ₃ as a catalyst. According to this description, an increase in the rate of formation is necessary to control the formation ratio of CFCs below 2%. However, there is no detailed description of the actual educational relationship. Similarly, in the publication USP No. 5,399,549 discloses a production process for HFC-125 from the same starting material by a gas phase reaction using Cr ₂ O ₃ as a catalyst. However, there is no detailed description of the formation ratio of CFCs.

On the other hand, in the Japanese Patent Laid-Open Publication No. 247,883 / 94 discloses a production process for HFC-125 characterized by a controlled low level of formed CFCs using an alumina catalyst fluorinated to over 70% in a fluorination reaction of HCFC-123 or HCFC-124. Although in this production method, at a reaction temperature of 350 ° C, the amount of CFCs formed in the fluorination reaction of HCFC-123 with the alumina catalyst is 0.5%, the ratio of CFCs / HFC-125 is about 1.1% ,

A fluorination process for tetrachlorethylene with a fluorinated alumina catalyst is disclosed in U.S. Pat Japanese Patent Laid-Open Publication No. 505,328 / 91 which discloses a process which uses an alumina catalyst containing over 90% by weight of AlF ₃ and carries metals such as Cr and Mn. However, this publication does not contain a description of impurities such as CFCs.

Although similar procedures in the Japanese Patent Laid-Open Publication No. 247,884 / 94 and in the Japanese Patent Laid-Open Publication No. 97,725 / 93 With respect to other methods, the amount of CFCs formed in both is high: at a reaction temperature of 350 ° C, the amount of CFCs formed is 1.7% in the first method and at a reaction temperature of 360 ° C, it is 2 to 3% in the latter method.

Moreover, in the Japanese Patent Laid-Open Publication No. 146,832 / 89 discloses a method of fluorination reaction of tetrachlorethylene using a chromium catalyst. The catalyst is Cr ₂ O ₃ prepared by pyrolysis of ammonium dichromate. However, the amount of CFCs formed is nowhere mentioned.

In the Japanese Patent Laid-Open Publication No. 268,933 / 96 discloses a fluorination process of tetrachlorethylene which uses a mixed catalyst of MgO and Cr ₂ O ₃ . Experiments were carried out with different mixed catalysts with different ratios of the amounts of MgO to Cr ₂ O ₃ . By using a catalyst having a Cr content which minimizes the ratio of CFCs / HFC-125, the conversion rate of tetrachlorethylene is at a reaction temperature of 320 ° C about 93%, and the ratio of CFCs / HFC-125 is 2.9%. The amount of CFCs formed itself is lower when the ratio of MgO is higher, while the conversion rate of tetrachlorethylene is lower; It has also been shown that increasing the Cr content to obtain a higher conversion rate results in a maximum of two fold increase in the amount of CFCs formed.

The EP-A-0 514 932 relates to fluorination catalysts and to a process for fluorination of halogenated hydrocarbons in a gas phase in the presence of a fluorination catalyst, in which the fluorination catalyst may be a fluorinated chromium-containing catalyst.

The EP-A-0 641 598 relates to a chromium-containing fluorination catalyst, a process for producing the catalyst, and a fluorination process using the catalyst in which the catalyst is partially fluorinated.

Object of the invention

The The present invention has been made in view of the above situation made. The task is to improve by the in the fluorination reaction used catalyst, a production process for fluorine-containing Provide ethane in which the formation of CFC by-products so low as possible can be regulated when the fluorine-containing ethane with HFC-125 as Main reaction product is obtained by a fluorination reaction, the tetrachlorethylene or HCFC-123 or HCFC-124 as starting material used.

Essence of the invention

The Production method according to the invention for fluorine-containing Ethane, which has HFC-125 as a main component, by fluorination of at least one compound selected from the group consisting from tetrachlorethylene, HCFC-123 and HCFC-124, with hydrogen fluoride is characterized in that fluorochrome oxide as a catalyst is used, which has a fluorine content of not less than 30 wt .-%.

By increase the fluorine content of the fluorochrome oxide catalyst may be fluorine-containing Ethane can be produced with HFC-125 as the main component, while the Formation of CFC by-products can be controlled as low as possible, when this catalyst in the fluorination reaction of the above Starting material is used. In the thus produced fluorine-containing ethane, however, are in addition to HFC-125 HCFC-123 and / or HCFC-124, as described below.

The Starting material of the present invention is either a single material, which is selected from tetrachlorethylene, HCFC-123 and HCFC-124, or a mixture of two or more thereof.

The mentioned above HCFC-124 can be synthesized, for example, by fluorination of HCFC-123 or by reduction of CFC-114a (2,2-dichloro-1,1,1,2-tetrafluoroethane) to be obtained. For example, the above-described HCFC-123 by fluorination of tetrachlorethylene, by chlorination of HCFC-133a (2-chloro-1,1,1-trifluoroethane) or by reduction of CFC-113a (1,1,1-trichloro-2,2,2-trifluoroethane) to be obtained. Furthermore For example, the tetrachlorethylene described above is replaced by an industrially common one Process, for example by chlorination of hydrocarbons or their chlorine derivatives at their own pyrolysis temperature, produced.

Even if now a fluorination reaction by HF using this chosen Starting materials performed can, the ratio can of CFCs / HFC-125 is not kept low by conventional methods become. The mechanism of formation of CFCs as by-products will be described below.

If the starting material is HCFC-124, then the conversion rate in HFC-125 under ordinary Reaction conditions do not reach 100%, and unreactive HCFC-124 is present in the reactor. This unreactive HCFC-124 will form HCFC-123, which results from the reaction with a by-product, HCl.

If on the other hand, the starting material HCFC-123 is, then the organic substances at the reactor outlet after the fluorination reaction mainly fluorinated HCFC-124, HFC-125, HCl chlorinated tetrachlorethylene, which is a by-product, and unreactive HCFC-123.

If the starting material is tetrachlorethylene, then the organic Substances at the reactor outlet in similar Way mainly HCFC-123, HCFC-124 and HFC-125.

Out These gases, which pass through the reactor, the gas with HFC-125 as the main component separated, and the remaining Recycled gas to the reactor (recycled), to improve the yield. This way, regardless of Starting material, the fluorination of the mixture, which consists mainly Tetrachlorethylene, HCFC-123 and HCFC-124 persist in the reactor, although the quantity is different. For this reason are HCFC-133a and HFC-134a (1,1,1,2-tetrafluoroethane), the by-products are when tetrachlorethylene is used as the starting material, and CFCs such as CFC-113a, CFC-114a and CFC-115. CFCs formed in such reactions are not affected by the fluorination reaction implemented in HFC-125 and are lost in the production. The Whole CFC-113a and CFC-114a is made by recycling the reaction gases fluorinated to CFC-115. As the boiling point of CFC-115 is close to that of HFC-125 and the relative volatility is close to 1, is the separation in an ordinary Fractionator difficult. Their separation requires separate facilities for extractive distillation, which will increase the manufacturing cost. moreover CFCs are banned substances as described below since they are the Destroy ozone layer, and it is necessary to minimize their release to the global To protect the environment. Therefore, the amounts of CFCs formed, including CFC-115, as far as possible be reduced.

The Inventors of the present invention seriously have a fluorination reaction of tetrachlorethylene, HCFC-123 and HCFC-124 studied the to achieve the present invention, and have found that The relationship of CFCs / HFC-125 (when tetrachlorethylene is used as starting material, then the ratio of CFCs to the entire HCFC-123, HCFC-124 and HFC-125) than 0.5%, when a fluorination reaction using a fluorochrome oxide catalyst, in which the content of fluorine is not less than 30% by weight a reaction temperature of 300 ° C is performed, if tetrachlorethylene is used as starting material, not less than 1.0%, when HCFC-123 is used as starting material, and nothing more than 0.1%, when HCFC-124 is used as the starting material at a reaction temperature from 315 ° C.

As the chromium oxide necessary for the preparation of the catalyst, one which is highly active having a specific surface area of not less than 120 m ² / g is preferable, as in US Pat Japanese Patent Laid-Open Publication No. 146,680 / 93 disclosed. In the present invention, the chromium oxide is further fluorinated to have a fluorine content of not less than 30% by weight and subjected to the reaction. For this reason, when the chromium oxide (unfluorinated substance) is filled in the reactor, for example, the chromium oxide may be fluorinated in at least one of the steps immediately preceding the fluorination reaction of the above-described starting materials to obtain fluorochrome oxide.

The fluorination of the chromium oxide may be carried out using any known method, such as that described in U.S. Pat Japanese Patent Laid-Open Publication 146,680 / 93 described be carried out. For example, to increase the fluorine content, the chromium oxide may be treated with HF at a high temperature for an extended period of time. In fact, fluoro-chromium oxide having a fluorine content of 31.4% by weight was obtained when the chromium oxide was treated with HF at 360 ° C for 220 hours.

In The present invention can be achieved by one of those described above The method of various methods produces fluorochrome oxide as well as by a catalyst already used in the fluorination reaction of halogenated hydrocarbons used fluorochrome oxide as suitable catalysts are used. Namely, when fluorochrome with a lower fluorine content before the reaction for a longer time in the fluorination reaction of halogenated hydrocarbons is used, then it becomes a higher fluorine content of not less than 30% by weight, which is for the present invention suitable is. Indeed was used in the experiment in which the fluorination reaction of HCFC-133a carried out was, the molar ratio of HF / HCFC-133a equal to 4 at a reaction temperature of 350 ° C for 140 hours was obtained, fluorochrome oxide having a fluorine content of 35.2 wt .-%.

The Inventors of the present invention have found that it is extremely important is not easy to fluoride the chromium oxide, but so it too fluorinate that it has a fluorine content of not less than 30% by weight having. According to the findings of the present inventors Invention will obtain the target compound HFC-125 with high selectivity and the formation of CFCs can be well controlled when the degree of fluorination (the fluorine content) of the chromium oxide was adjusted so that it does not less than 30 wt .-% is. The preferred range for the fluorine content is From 30% to 45% by weight.

In the present invention, the specific surface area of the fluorochrome oxide catalyst is usually 25 m ² / g to 130 m ² / g, and preferably 40 m ² / g to 100 m ² / g, although no specific limits are set.

The Fluorination reaction of the starting materials with HF in the present Invention becomes common at a reaction temperature of 250 to 400 ° C and preferably at 280 to 350 ° C performed. If the Contact temperature and the molar ratio are the same, then increases the conversion rate to HFC-125 with increasing reaction temperature. However, it is necessary to carefully select the reaction temperature since this one big one Has an effect on the amount of by-products formed.

Also in the present invention is the ratio of in the fluorination reaction used HF to the starting material as described above not specifically limited. However, the molar ratios of HF to tetrachlorethylene, from HF to HCFC-124 and from HF to HCFC-123 usually in the range 1.5: 1 to 15: 1 and preferably in the range 2: 1 to 9: 1. It is particularly preferred the fluorination reaction while increasing the ratio to carry out the HF quantity, to reduce the amount of CFCs formed, which has the disadvantage indicates that they are the profitability of the process itself impaired because it increases the amount of recycled HF. That's why the implementation the fluorination reaction taking into account both conditions well-balanced individual reaction conditions more practical.

In however, there is no particular limit to the present invention with regard to the pressure of the fluorination reaction of the starting materials, however, this can be determined on the basis of these conditions Be as the separation of the products and the cleaning process are advantageous under certain pressure conditions. The reaction pressures are usually in the range of 0.01 MPaG to 2.0 MPaG.

In The present invention is the gas containing HFC-125, which the major component represented by the fluorination reaction of the starting material, separated and recovered once. Thereafter, the residue containing HCFC-123 and / or HCFC-124 recycled several times into the reactor. This is associated with an improvement in the yield of HFC-125, and one of the most significant results of this invention is that The formation of CFCs can also be regulated by this recycling can.

If the present invention is carried out, then it is sometimes necessary, on the phenomenon the degradation of the catalyst with time to pay attention.

If the degradation of the catalyst in the present invention particularly is problematic, then it is preferred and effective, 0.1 mol% To include 10 mol% of oxygen in the starting material to the To effectively prevent degradation.

Industrial applicability

In the manufacturing process for fluorine-containing ethane of the present invention may fluorine-containing ethane with HFC-125 as a main component with a high degree of regulation with regard to the formation of CFCs as a highly specific Fluorochrome oxide having a fluorine content of not less than 30% by weight is used as a catalyst when used either individually or as a mixture of from the group consisting of tetrachlorethylene, HCFC-123 and HCFC-124 are selected Starting materials are fluorinated with hydrogen fluoride.

example

The The following examples are given to the present invention to clarify further. However, it should be understood that the present Invention is not limited to these examples.

example 1

The fluorochrome oxide catalyst was prepared as described below. First, 10% ammonia water was added to 765 g of 5.7% aqueous chromium nitrate solution. After filtering and washing the resulting precipitate, it was air dried at 120 ° C for 12 hours to give chromium hydroxide. This chromium hydroxide was formed into pellets of 3.0 mm in diameter and 3.0 mm in height, which calcined at 400 ° C for 2 hours in a stream of nitrogen gas to give chromium oxide.

Next, the chromium oxide was gradually heated to 200 ° C to 360 ° C, and after reaching 360 ° C, it was fluorinated with hydrogen fluoride for 220 hours to give fluorochrome oxide. The specific surface area of this fluorochrome oxide obtained by the BET method was 70 m ² / g and the fluorine content was 31.4 wt%.

• *W: Katalysatorgewicht (g), Fo: Gasströmungsgeschwindigkeit, umgerechnet in den Standardzustand (ml/sec).

Subsequently, using this fluorochrome oxide as a catalyst, a fluorination reaction of HCFC-124 was carried out under the following conditions: 10 g of catalyst was used; the flow rate of the HCFC-134 was 50 Nml / min; the flow rate of the HF was 100 Nml / min; W / Fo was 4 (g · sec · Nml ^-1 ); the molar ratio of HF / HCFC-124 was 4; and the reaction temperature was 315 ° C. Then, the catalyst for the reaction was placed in a Hastelloy C reaction tube of 15 mm in inner diameter. After washing the reaction gas with water, it was analyzed by gas chromatography using a Polapack Q column. The results are shown in Table 1. Table 1 W / Fo HF / HCFC-124 molar ratio Reaction temperature (° C) Concentration of organic substances (%) CFCs / HFC-125 (%) HCFC-123 HCFC-124 HFC-125 CFCs 4 2 315 10.9 33.3 55.6 0.123 0.221

• * W: Catalyst weight (g), Fo: Gas flow rate, converted to the standard state (ml / sec).

Example 2

The fluorination reaction of HCFC-124 was carried out under conditions similar to Example 1, except that fluorochrome oxide (fluorine content: 35.2% by weight) was used in the fluorination reaction of HCFC-133a. The reaction results are shown in Table 2. Table 2 W / Fo HF / HCFC-124 molar ratio Reaction temperature (° C) Concentration of organic substances (%) CFCs / HFC-125 (%) HCFC-123 HCFC-124 HFC-125 CFCs 4 2 315 10.6 40.4 48.9 0.073 0,150

Example 3

The fluorination reaction of HCFC-124 was conducted under similar conditions to Example 1 except that fluorochrome oxide (fluorine content: 41.5% by weight) was used in the fluorination reaction of HCFC-133a. The reaction results are shown in Table 3. Table 3 W / Fo HF / HCFC-124 molar ratio Reaction temperature (° C) Concentration of organic substances (%) CFCs / HFC-125 (%) HCFC-123 HCFC-124 HFC-125 CFCs 4 2 315 10.4 47.4 42.1 0,042 0,099

Comparative Example 1

The fluorination reaction of HCFC-124 was carried out under conditions similar to Example 1, except that a catalyst (specific surface area: 140 m ² / g, fluorine content: 12% by weight, referred to as a "low-fluorinated catalyst") , which under conditions for the fluorination of Chro had been obtained at 200 ° C for 2 hours. The reaction results are shown in Table 4. Table 4 W / Fo HF / HCFC-124 molar ratio Reaction temperature (° C) Concentration of organic substances (%) CFCs / HFC-125 (%) HCFC-123 HCFC-124 HFC-125 CFCs 4 2 315 11.1 26.0 62.6 0.176 0.281

Example 4

The fluorination reaction of HCFC-124 was conducted under conditions similar to Example 2, except that the flow rate of HCFC-124 was 100 Nml / min, the flow rate of HF was 200 Nml / min and W / Fo was 2 (g · Sec · Nml ^-1 ). The reaction results are shown in Table 5. Table 5 W / Fo HF / HCFC-124 molar ratio Reaction temperature (° C) Concentration of organic substances (%) CFCs / HFC-125 (%) HCFC-123 HCFC-124 HFC-125 CFCs 2 2 315 6.7 56.6 36.6 0.037 0,100

Comparative Example 2

The fluorination reaction of HCFC-124 was carried out under conditions similar to those in Example 1, except that a catalyst (fluorine content: 25% by weight) obtained under conditions for the fluorination of chromium oxide at 360 ° C for 155 hours was, was used. The reaction results are shown in Table 6. Table 6 W / Fo HF / HCFC-124 molar ratio Reaction temperature (° C) Concentration of organic substances (%) CFCs / HFC-125 (%) HCFC-123 HCFC-124 HFC-125 CFCs 4 2 315 11.0 28.2 60.3 0,157 0.260

Comparative Example 3

The fluorination reaction of HCFC-124 was carried out under conditions similar to Example 4, except that the low fluorinated catalyst used in Comparative Example 1 was used. The reaction results are shown in Table 7. Table 7 W / Fo HF / HCFC-124 molar ratio Reaction temperature (° C) Concentration of organic substances (%) CFCs / HFC-125 (%) HCFC-123 HCFC-124 HFC-125 CFCs 2 2 315 8.2 44.6 47.1 0.081 0.172

Example 5

The fluorination reaction of HCFC-124 was carried out under similar conditions to Example 2 except that the molar ratio of HF / HCFC-124 to 4 was the flow rate from HCFC-124 to 30 Nml / min and the flow rate of HF to 120 Nml / min. The reaction results are shown in Table 8. Table 8 W / Fo HF / HCFC-124 molar ratio Reaction temperature (° C) Concentration of organic substances (%) CFCs / HFC-125 (%) HCFC-123 HCFC-124 HFC-125 CFCs 4 4 315 6.5 40.7 52.7 0,044 0.084

Comparative Example 4

The fluorination reaction of HCFC-124 was carried out under conditions similar to Example 5, except that the low fluorinated catalyst used in Comparative Example 1 was used. The reaction results are shown in Table 9. Table 9 W / Fo HF / HCFC-124 molar ratio Reaction temperature (° C) Concentration of organic substances (%) CFCs / HFC-125 (%) HCFC-123 HCFC-124 HFC-125 CFCs 4 4 315 6.6 31.0 62.2 0.079 0,128

Example 6

The fluorination reaction was carried out under conditions similar to Example 2, except that HCFC-123 was used as the starting material, the flow rate of HCFC-123 to 30 Nml / min, the flow rate of HF to 120 Nml / min, W / Fo to 4 (g · sec · Nml ^-1 ), the molar ratio of HF / HCFC-123 to 4 and the reaction temperature to 315 ° C was set. The reaction results are shown in Table 10. Table 10 W / Fo HF / HCFC-123 molar ratio Reaction temperature (° C) Concentration of organic substances (%) CFCs / HFC-125 (%) HCFC-123 HCFC-124 HFC-125 CFCs 4 4 315 35.4 32.9 31.2 0,251 0.806

Comparative Example 5

The fluorination reaction of HCFC-123 was carried out under conditions similar to those in Example 6, except that the low fluorinated catalyst used in Comparative Example 1 was used. The reaction results are shown in Table 11. Table 11 W / Fo HF / HCFC-123 molar ratio Reaction temperature (° C) Concentration of organic substances (%) CFCs / HFC-125 (%) HCFC-123 HCFC-124 HFC-125 CFCs 4 4 315 29.1 29.9 40.4 0,432 1.07

Example 7

Using the same catalyst as in Example 2, the fluorination reaction was carried out using tetrachlorethylene (referred to as C ₂ Cl ₄ in the table) as a starting material. The reaction was carried out under the following conditions: the amount of tetrachlorethylene supplied was 0.22 g / min; the flow rate of HF was 270 Nml / min; the molar ratio of HF / tetrachlorethylene was 9; and W / Fo was 2. The reaction results are shown in Table 12. Here, in the reaction of tetrachlorethylene, the ratios of CFCs to the entire HCFC-123, HCFC-124 and HFC-125 (hereinafter referred to as 12X) are shown in the table. Table 12 W / Fo HF / C ₂ Cl ₄ molar ratio Reaction temperature (° C) Concentration of organic substances (%) CFCs / 12X (%) HCFC-123 HCFC-124 HFC-125 CFCs 2 9 300 22.3 13.6 4.01 0.169 0.423

Comparative Example 6

The fluorination reaction of tetrachlorethylene was conducted under conditions similar to Example 7, except that the catalyst used in Comparative Example 1 was used in the reaction of Example 7. The reaction results are shown in Table 13. Table 13 W / Fo HF / C ₂ Cl ₄ molar ratio Reaction temperature (° C) Concentration of organic substances (%) CFCs / 12X (%) HCFC-123 HCFC-124 HFC-125 CFCs 2 9 300 25.1 13.0 2.81 0,271 0.662

Example 8

The fluorination reaction of tetrachlorethylene was carried out under conditions similar to Example 7, except that 1 mol% of oxygen was added to tetrachlorethylene in the reaction gas. The reaction results are shown in Table 14. A significant reduction in catalyst activity by degradation was not observed even after a reaction over 1,000 hours. Table 14 W / Fo HF / C ₂ Cl ₄ molar ratio Reaction temperature (° C) Concentration of organic substances (%) CFCs / 12X (%) HCFC-123 HCFC-124 HFC-25 CFCs 2 9 300 15.4 6.80 1.22 0.311 1.33

Comparative Example 7

The fluorination reaction of tetrachlorethylene was carried out under similar conditions to Example 8, except that the catalyst used in Comparative Example 1 was used in the reaction of Example 8. The reaction results are shown in Table 15. Table 15 W / Fo HF / C ₂ Cl ₄ molar ratio Reaction temperature (° C) Concentration of organic substances (%) CFCs / 12X (%) HCFC-123 HCFC-124 HFC-125 CFCs 2 9 300 16.2 7.49 1.37 0.385 1.54

As shown in each example, it can be seen that when catalysts satisfying the conditions of the present invention are used in the fluorination reactions of the starting materials, the formation of CFCs can be completely controlled and the target products can be obtained with good selectivity even if the reaction conditions and the starting material are modified. In contrast, as shown in each comparative example, the use of catalysts under conditions other than conditions of the invention will have no significant effect on the regulation of CFC formation.

Claims (4)

A fluorine-containing ethane production process, characterized in that fluorochrome oxide having a fluorine content of not less than 30% by weight is used as a catalyst when fluorine-containing ethane containing 1,1,1,2,2-pentafluoroethane as the main component and 2-chloro -1,1,1,2-tetrafluoroethane and / or 2,2-dichloro-1,1,1-trifluoroethane as reaction products, by fluorinating at least one compound selected from the group consisting of tetrachlorethylene, 2,2-dichloro -1,1,1-trifluoroethane and 2-chloro-1,1,1,2-tetrafluoroethane, with hydrogen fluoride, wherein 2-chloro-1,1,1,2-tetrafluoroethane and / or 2,2-dichloro -1,1,1-trifluoroethane from the reaction mixture in the fluorination reaction are mainly circulated. Production method for fluorine-containing ethane after Claim 1, wherein the fluorine content of the fluorochrome oxide catalyst 30 to 45 wt .-% is. Production method for fluorine-containing ethane after Claim 1, wherein the fluorochrome oxide catalyst by fluorination reaction made of chromium oxide. Production method for fluorine-containing ethane after Claim 1, wherein the fluorochrome oxide catalyst, which by Fluorination reaction of halogenated hydrocarbons formed is used as the fluorochrome oxide catalyst.